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  • Title: Microbial transformations of two lupane-type triterpenes and anti-tumor-promoting effects of the transformation products.
    Author: Akihisa T, Takamine Y, Yoshizumi K, Tokuda H, Kimura Y, Ukiya M, Nakahara T, Yokochi T, Ichiishi E, Nishino H.
    Journal: J Nat Prod; 2002 Mar; 65(3):278-82. PubMed ID: 11908965.
    Abstract:
    Microbial transformation of betulin (1), a lupane-type triterpene obtained from the bark extract of white birch (Betula platyphylla Sukatshev var. japonica), and its chemical oxidation product, betulonic acid (2), by the fungus Chaetomium longirostre yielded 4,28-dihydroxy-3,4-seco-lup-20(29)-en-3-oic acid (3) and 4-hydroxy-3,4-seco-lup-20(29)-ene-3,28-dioic acid (4) from 1, and 4,7beta,17-trihydroxy-3,4-seco-28-norlup-20(29)-en-3-oic acid (5) and 7 beta,15 alpha-dihydoxy-3-oxolup-20(29)-en-28-oic acid (6) from 2. The four metabolites, 3-6, along with 1 and 2, were evaluated for their inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced by the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) in Raji cells as a primary screening test for inhibitors of tumor promotion. All of the triterpenes tested showed potent inhibitory effects, with the four metabolites 3-6 exhibiting the more potent effects.
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